In Black Money, Frontline correspondent Lowell Bergman investigates this shadowy side of international business, shedding light on multinational companies that have routinely made secret payments — often referred to as “black money” — to win billions in business. “The thing about black money is you can claim it’s being used for all kinds of things,” the British reporter David Leigh tells Bergman. “You get pots of black money that nobody sees, nobody has to account for, … you can do anything you like with. Mostly what happens with black money is people steal it because they can.”

Leigh knows. In his groundbreaking reporting for The Guardian newspaper, he helped uncover one of the biggest and most complicated cases currently under investigation — a story involving a British aerospace giant, the Saudi royal family, and an $80 billion international arms deal known as Al Yamamah, or “The Dove” in Arabic. “If there was one person who was the main man behind this arms deal, it turned out it was the U.S. ambassador, Prince Bandar bin Sultan,” says Leigh.

It all started back in 1985, when the charismatic Prince Bandar was put in charge of acquiring new fighter jets for the Saudi Arabian air force. The Israeli lobby in Congress reportedly stood in the way of the United States making a deal with the Saudis, so President Ronald Reagan sent Bandar to the British. The prince approached a willing Prime Minister Margaret Thatcher, and they sealed the massive deal between the United Kingdom, BAE Systems (formerly British Aerospace) and the Royal Saudi Air Force.

Rumors swirled that billions in bribes had changed hands to secure the deal, but British officials denied wrongdoing. “Of course there is suspicion, and of course people are entitled to be suspicious,” says Lord Timothy Bell, who was involved in the deal from the beginning on behalf of the Thatcher government. “But as far as I’m concerned, if the British government … and the Saudi government reached a sovereign agreement over an arms contract that resulted in a tremendous number of jobs in Britain, a great deal of wealth creation in Britain, … and enabled Saudi Arabians to defend themselves, … I think that’s a jolly good contract.”